In the past, certain operations of electronic circuit board assembly were performed away from the main production assembly systems. While various feeder machines and robotic handling systems would populate electronic circuit boards with integrated circuits, the operations related to processing integrated circuits, such as programming, testing, calibration, and measurement were performed in separate areas on separate equipment rather than being integrated into the main production assembly systems.
For example, in the programming of programmable devices such as electrically erasable programmable read-only memories (EEPROMs) and Flash EEPROMs, separate programming equipment was used which was often located in a separate area from the circuit board assembly systems. There were a number of reasons why programming was done off-line.
First, the programming equipment was relatively large and bulky. This was because of the need to accurately insert and remove programmable devices at high speeds into and out of programming sockets in the programmer. Since insertion and removal required relatively long traverses at high speed and very precise positioning, very rigid robotic handling equipment was required. This rigidity requirement meant that the various components had to be relatively massive with strong structural support members to maintain structural integrity and precision positioning of the pick and place system moving at high speeds. Due to the size of the programming equipment and the limited space for the even larger assembly equipment, they were located in different areas.
Second, a single high-speed production assembly system could use up programmed devices faster than they could be programmed on a single programming mechanism. This required a number of programming systems, which were generally operated for longer periods of time in order to have a reserve of programmed devices for the production assembly systems. This meant that the operating times and the input requirements were different between the two systems.
Third, no one had been able to build a single system which could be easily integrated with both the mechanical and electronic portions of the production assembly systems. These systems are complex and generally require a great deal of costly engineering time to make changes to incorporate additional equipment.
A major problem associated with programming the programmable devices in a separate area and then bringing the programmed devices into the production assembly area to be inserted into the electronic circuit boards was that it was difficult to have two separate processes running in different areas and to coordinate between the two separate systems. Often, the production assembly system would run out of programmable devices and the entire production assembly system would have to be shut down. At other times, the programming equipment would be used to program a sufficient inventory of programmed devices to assure that the production assembly system would not be shut down; however, this increased inventory costs. Further problems were created when the programming had to be changed and there was a large inventory of programmed integrated circuits on hand. In this situation, the inventory of programmable devices would have to be reprogrammed with an accompanying waste of time and money.
While it was apparent that a better system would be desirable, there appeared to be no way of truly improving the situation. There were a number of apparently insurmountable problems that stood in the way of improvement.
First, the operating speeds of current production assembly systems so greatly exceeded the programming speed capability of conventional programmers that the programmer would have to have a much greater through-put than thought to be possible with conventional systems.
Second, not only must the programmer be faster than existing programmers, it would also have to be much smaller. The ideal system would integrate into a production assembly system, but would do so without disturbing an existing production assembly system or requiring the lengthening of a new production assembly system over that of the length without the ideal system. Further, most of these production assembly systems were already filled with, or designed to be filled with, various types of feeding and handling modules which provide limited room for any additional equipment.
Third, any programmer integrated with the production assembly system would apparently also have to interface with the control software and electronics of the production system software for communication and scheduling purposes. This would be a problem because production assembly system software was not only complex, but also confidential and/or proprietary to the manufacturers of those systems. This meant that the integration must be done with the cooperation of the manufacturers, who were reluctant to spend engineering effort on anything but improving their own systems, or must be done with a lot of engineering effort expended on understanding the manufacturers' software before working on the programmer's control software.
Fourth, the mechanical interface between a programmer and the production equipment needed to be highly accurate for placing programmed devices relative to the pick-and-place handling equipment of the production assembly system.
Fifth, there are a large number of different manufacturers of production handling equipment as well as production manufacturing equipment. This means that a large number of different production assembly system configurations would have to be studied and major compromises in design required for different manufacturers.
Sixth, the ideal system would allow for changing quickly between different micro devices having different configurations and sizes.
Seventh, the ideal system needed to be able to accommodate a number of different micro device feeding mechanisms including tape, tube, and tray feeders.
Finally, there was a need to be able to quickly reject micro devices which failed during the programming.
All the above problems seemed to render an effective solution impossible. This was especially true when trying to invent a comprehensive system which would be portable, allow “plug and play” operation with only external electric and air power, provide automated programming and handling, and be able to present programmed programmable devices to an automated production assembly system.